In the continuation of a collaborative project with Humboldt University in Berlin, Dr. Haike Leibiger has joined the CCRC and is characterizing the N- and O-linked carbohydrates on two IgM antibodies. The polyspecific antibody has five N-linked sites on the m chain, and the monospecific IgM has an additional potential N-glycosylation site in the variable region of its m-chain. The goal is to understand the structural roles of the carbohydrates in relation to the activity and stability of the proteins. The antibodies have been cleaved by trypsin and the fragments separated by HPLC. Preliminary characterization of the peptides and glycopeptides by mass spectroscopy (MALDI-TOF) has been performed. Location of the carbohydrates, prior to their identification, is being pursued using MS and other techniques, before and after treatment of the tryptic fragments with N-glycanase.